Project Summary This is the revised second competing renewal of a Program Project (PP) focused on investigating the role that age-related changes in autophagy play in the functional alterations and inefficient stress response of old organisms. The programmatic approach has allowed us to establish previously unknown connections between autophagy, an essential component of the proteostasis network, and key cellular processes in biology of aging such as metabolism, immune response/inflammation and the stress response. The expansion of our team of experts and the conceptual and technical maturation of the program have placed us in an ideal position to contribute to test the Geroscience hypothesis that aging is the major risk factor for common chronic diseases and that modulating processes that contribute to aging could set the basis for new interventions to ameliorate aging-related disorders. We propose to use modulation of autophagy as a way to prevent or delay proteotoxicity and proteostasis loss associated with Alzheimer?s disease and related dementias (AD/ADRD). The components of the PP are four Projects involving 8 faculty members from 6 academic departments and four Cores that provide support to the research activities of the four projects. The projects share ideas, techniques and experimental models. Completion of aims in each project requires participation of members from several of the Projects and Cores. The PP activities are reviewed periodically by the executive committee, and an internal (Einstein Faculty) and external (faculty at other institutions) Scientific Advisory Committee. The long-term goal of the PP remains testing the overall hypothesis that impairment in autophagy in elders mediates the functional deterioration and increases vulnerability to proteotoxicity associated with diseases, in this case AD. Building on the novel findings of the previous period, we propose now the following specific aims: 1) to determine the impact of AD-associated proteotoxicity on proteostasis and activity of three main autophagic pathways CMA (P1, P3), MA (P4, P3) and eMI (P1, P2, P3) in peripheral tissues (liver, adipose tissue, pancreas, skeletal muscle) (P1, P4) and the immune and hematopoietic systems (P2, P3). 2) to determine the contribution of lymph in the transference of the aging and AD-related signature of brain proteotoxicity to peripheral tissues (P1, P2, P4); 3) to determine the impact of loss of autophagy-dependent proteostasis in peripheral tissues (P1, P4) and the immune system (P3) on AD-related proteotoxicity progression and 4) to analyze the effect on AD- related proteotoxicity of genetic (P1, P3), chemical (P1, P3, P4) and dietary (P2, P3, P4) interventions that enhance/restore normal autophagy in old organisms. These studies will require the synergistic cooperation of groups with expertise in aging, AD-related proteotoxicity, autophagy, proteostasis, dendritic cell function, T cell biology, hematopoiesis, lymph, lipid and glucose metabolism, nutrient sensing, medicinal chemistry, advanced high-resolution and in vivo imaging, drug development, and data analysis and integration. Relevance: We explore the novel concept that interventions to restore/enhance autophagy could be applied as anti-aging strategies to prolong health-span and ameliorate AD-related proteotoxicity. Our studies may ultimately provide pre-clinical evidence of the value of autophagy targeting in the treatment of AD/ADRD.